For personal computers, various kinds of e-mail software have been developed by which e-mail to be transmitted is generated in the form of text or binary data. Some types of software have the function of a scheduler, or an animation function which looks as if a popular animation character is transmitting an e-mail (please refer to JP2001-222475). A user of a personal computer can select from various kinds of e-mail software, and install the selected software in a personal computer for use.
In recent years, it has become possible to transmit and receive e-mails not only by using a personal computer such as a desktop but also by a portable communication terminal such as a mobile phone. In a mobile phone which can transmit and receive e-mails, e-mail software is installed as native software. That is to say, the e-mail software available to a user of a mobile phone is limited to the software which is already installed in a mobile phone by the manufacturer. Consequently, a user cannot install and use software of his or her choice.
On the other hand, it is known that a user is able to install optional application software in a mobile phone. At the time of using software other than native software, the above mobile phone, for example, performs a packet communication with a server connected to the Internet, and downloads and installs application software generated by using a Java® programming language. It seems that the above problem can be solved by distributing e-mail software to the above mobile phone. However, from the viewpoint of protecting personal information stored in a mobile phone, the functionality of an application is limited to performing in accordance with the downloaded application software. For example, an application can read or write data only in a storage area assigned to an application by a mobile phone, or an application can communicate only with a server which downloads application software.
It is necessary to communicate with a mail server so that an application transmits and receives an e-mail. However, a conventional mobile phone operates a mailer in accordance with e-mail software downloaded from the Internet, and the mailer attempts to communicate with a mail server, but the mailer cannot communicate with a mail server due to the limitations described above.
Further, if a mailer, which is a native software, operated in accordance with an e-mail program receives an e-mail generated for a mailer operated in accordance with downloaded e-mail software (hereafter referred to as “Java mailer” since it is generated by using a Java programming language), the received e-mail is stored in a storage area that is different from a storage area for a Java mailer. That is to say, although an e-mail generated for a Java mailer is received successfully, the e-mail cannot be opened by a Java mailer.